One Londoner and an American geologist are out for a bicycle trip in the Thames valley. They talk about natural disasters and volcanic eruptions and how thankful they are that such things do not happen in these regions and at these times. The next morning will however prove them wrong and the Londoner will have to ride for his life to escape a catastrophic volcanic eruption.

Grant Allen was a Canadian writer who lived in the period 1848 – 1899. His writing career began around 1876 when he published a series of essays on science. His first books, "Physiological Aesthetics" and "Flowers and Their Pedigrees" took up this subject as well. Grant Allen was also a pioneer in science fiction. He wrote about thirty science fiction novels in the period 1884-1899. In his later works, Allen also took up some revolutionary theories for the time regarding marriage. "The Woman Who Did" which depicts the life of an independent woman who takes care of her child on her own became a bestseller.